1. Field of the Invention
This invention pertains to a structural laminate having a plastic surface finish coat laminated to a structural base, which is useful in manufacturing wall units, building panels, furniture, cabinets, and plumbing ware. Useful items which may be manufactured by the practice of this invention include shower stalls, tubs and sinks.
2. Description of the Prior Art
Fiber glass reinforced materials are used in making structural panels and shaped articles. The large quantities of organic resin necessary for structural integrity of such articles renders them costly to produce. One proposed solution employs inorganic materials such as gypsum as a substitute for the costly resin used in the structural base. The inorganic materials used in the structural base should have adequate physical properties and a good bond to the plastic surface finish to provide structural integrity to the laminated product. The plastic surface finish is preferably a polyester gel coat or acrylic resin which provide water and stain resistance, colorfastness, durability and cleanability.
U.S. Pat. No. 3,868,296, to McKeon, Jr., et al teaches a plaster structural unit with a water impervious face, an intermediate layer of fiber glass reinforced resin, a second intermediate layer of organic resin mixed with protruding wood chips, and a backing layer of gypsum. The wood chips and the second intermediate layer protrude from the resin to engage the gypsum layer bonding it to the laminate. The chips have relatively low tensile strength and are bulky, on the order of one-fourth to one-half inch wide, so that the layer containing the chips must inherently be relatively thick, from 0.2 to 0.5 inches.